Centrifuge for separating solids from slimy masses



Nov. 25, 1958 G. LlNKE ET AL CENTRIFUGE FOR SEPARATING soLIDs FROM SLIMYMAssEs Filed Jan. 2o. 1955 4 Sheets-Sheet 1 Fig. l

IAB

ngz

Nov. 25, 1958 G. LINKE ET AL CENTRIFUGE FOR SEPRATING SOLIDS FROM SLIMYMASSES Filed Jan. 20. 1955 4 Sheets-Sheet 2 figs WIM

w .f, W Ww f Nov. 25, 1958 G. LINKE ET AL 2,861,691

CENTRIFUGE FOR SEPARATING soLIDs FROM SLIMY MAsSEs 4 Sheets-Sheet 3Filed Jan. 20. 1955 .j-L-X i1 a es 26 am L Nov. 25, 1958 i G. LINKE ETAL2,861,691

CENTRIFUGE FOR SEPARATING soLIns FROM SLIMY MAssEs Filed Jan. 20. 1955 4Sheets-Sheet 4 figs 2S United States PatentA O CENTRIFUGE FOR SEPARATINGSOLIDS FRO SLlVIY MASSES 'Gerhard Linke and Hans-Heinrich Hlsen, Mulheim(Ruhr), and Fritz Kleinlein, Aachen, Germany Application January 20,1955, Serial No. 433,158

Claims priority, application Germany January 21, 1954 12 Claims. (Cl.210-370) 'This invention relates to centrifuges for separating `viscousor slimy masses from their liquid carrier. Such :masses may comprisepasty paint, rubber or plastic dispersions, emulsions, fertilizer orlike industrial salt compositions, sludges containing coal particles,mine Waste, or solutions containing sugar, solvents and the like.

In separating processes of the kind indicated it is es- :sential formany purposes that during the centrifuging .action the centrifuge drumor rotor should be caused to oscillate in the direction of the rotoraxis. In order to induce such oscillations, it is necessary to provideflexible or elastic connecting members between the relatively ro-.tatable parts and also to provide vibration-exciting means 'which arecapable of co-operating with machine parts :that rotate at a high rateof speed.

According to the invention a centrifuge for treating dispersions,emulsions, sludges and similar masses con- '.taining solid particles tobe separated from said masses is provided with a drive shaft, whichdrive shaft carries -on one of its ends conically shaped screening meansand guiding means which latter extend a short distance into saidscreening means, and which drive shaft co-operates :'-by way ofanti-friction type thrust bearings with abutting :means for elasticbuffer members, and is further provided xwith a housing which, whileacting as the other abutment `,for the said buffer members, isspring-supported from Va frame or base, and finally with motor-drivenvibrator -means adapted to cause the said drive shaft'and the meansassociated therewith to oscillate in an axial direction.

Also according to the invention, the said drive shaft and the screeningmeans fixedly associated therewith, which screening means preferablycomprise a centrifuging drum, are elastically coupled with thevibrating, spring- :supported housing in such a manner as to cause saiddrive 4shaft and associated means to vibrate, preferably in a resonantmanner, the arrangement being such that the spring elements may bestationary, while the said thrust `bearings are pre-loaded by saidspring elements. Thus, laccording to the invention, the 'rotary partsofthe centrifuge are structurally independent of the vibration-pro-.fducing means, it being possible, therefore, to design saidvibration-producing means as non-rotating dependable :elements of simpleconstruction.

The said guiding means, which are mounted on said `drive shaft, serve toguide and impel both the material being introduced into the centrifugeand the cake form- -ing on the wall of said drum. According to theinvention, said guide means may comprise a guiding cone member whichextends only for a short length into the 4centrifuge drum. In view ofthe fact that with this type of construction the said guide means donotr act as reinforcements for the centrifuge drum, the above-mentionedpre-loading of the thrust bearings by the elastic buffer lmembersbecomes of particular importance as regards the elimination ofchattering motion, this applying espe- -cial1y for horizontalcentrifuges as well Yas upwardly discharging centrifuges having moreunfavorable natural frequencies of vibration,

2,861,691 Patented Nov. 25, 1958 It is another object of the inventionto provide axial thrust bearings having a pre-load 20 percent greaterthan the maximum force introduced by the vibratory move ments.

A further feature of the invention resides in the provision of abuttingmeans in the form of spring retainers of which one retainer is directlyconnected with the housing of the thrust bearing, whereas the otherspring retainer is mounted on or integral with a sleeve which is in turnmounted for sliding movement and which is adapted to surround saidbearing housing.

These and other objects and advantages of the invention will becomefurther apparent from the following detailed description, referencebeing had to the accompanying drawings showing certain preferredembodiments of the invention.

. In the drawings:

Figure 1 is a fragmentary sectionalview of a centrifuge embodyingfeatures of the invention.

Figure 2 is a transverse section taken along the line A-B in Figure 1.

Figure 3 is a fragmentary sectional view of a modified form of theinvention.

Figure 4 is a fragmentaryv sectional view of a further modified form ofthe invention.

Figure 5 is a view similar to that of Figure 4.

Figure 6 is a fragmentary sectional View of a modified construction ofthe proposed vibration-producing means used in the embodiment of Figure4.

Referring now more particularly to the drawings, there is disclosed inFigures l and 2 a centrifuge system comprising a horizontal shaft 2having mounted on one end thereof a perforated or screen drum 1 intowhich the hereinabove mentioned mass is fedfrom a hopper 1a via a powerdriven screw conveyor 2a. The conical impeller and guide arrangement 3toward which said mass is moved `forms the hub of said drum 1. The shaft2 is driven by means of pulley 4. The shaft 2 is carried in cylindricalroller bearings 5mounted in the housing 6 in such a manner that, whilerotating, it can also oscillate in an axial direction.

These axial oscillations of said shaft 2 are produced by the rotatingeccentric weights 7 which are mounted for rotation in the frame member 8of the housing structure. The two eccentric weights 7 are driven forrotation by two known drive means 10 which are synchronized by two gearwheels 9 and which deliver their power to said weights through elasticuniversal-joint shafts 11. While the centrifugal forces set up by the.eccentric weights 7 are additive in a horizontal direction, i. e. inthe direction ofthe axis of shaft 2, they cancel each other out in avertical direction. It will be appreciated that the entire machine,which is elastically supported by helical springs 12, is caused by theeccentric weights 7 to oscillate in a horizontal direction, theseoscillations having a relatively small amplitude.

Arranged in the compartment 13 of the housing is a double-acting springarrangement 14 comprising rubber buffers or helical springs which aremounted between thrust bearings 15, the spring arrangement 14 beingcapable of rotating together with the rotor of the centrifuge. Thepre-load acting on the thrust bearings must be considerably greater,preferably by twenty percent,

than the alternating forces set up by the two masses which 14, whichconstitute the smaller. vibrating mass. ofthe system, will oscillate inan axial direction with an amplitude which is inversely proportional tothe weight or mass of the machine frame. The greater the correspondencebetween the frequency of the vibration-producing means 7 and the naturalfrequency of the oscillating system the greater the amplitude.

The characteristics of the oscillating system are given by the masses ofthe rotor 1, the shaft 2 the spring abutment 16, the spring constant ofthe spring arrangement 14 and the masses of the machine housing 6.

VAt its points of extreme deection the spring abutment 16 can in turnabut against the rubber buers 17,

this arrangement giving a non-harmonic spring character-v istic,reducing the tuning sensitivity of the system and improving theefficiency with which the filter cake is discharged by the axialvibrations of.v the centrifuge drum.

-In the embodiment of Figure 3, the reference numeral 18 indicates theconical centrifuge drum which is usually perforated but which may, ifdesired, have a continuous shell; this drum has a hollow hub 19 carryingguide means in the form of tins or blades toward which the material tobe processed is led in the direction of the arrow a and from which thematerial passes along the arrow b to the inside of the drum. The drum 18carries the centrifuged and thus dried material away in the direction ofthe arrow c, whereas the uid or liquid separated from the material willbe discharged in the direction of the arrows d through the perforationsof the drum or the screen-like lining thereof.

The centrifuge drum 18 is rigidly secured to the shaft 20 which isdriven for rotation by means of a clutch or coupling, a gearing or apulley 21. The shaft 2t) is carried in the bearings 22 mounted in thehousing 23 and in the housing section 24 of the vibration-producingmeans, respectively. The housing 23 and with it the centrifuge iselastically supported by rubber bulfers or springs 26 on a base orfoundation 25.

Provided in the housing section 24 Vis a circular partition 27 formingan abutment having a central aperture, which partition rests on eitherside against sets of springs or rubber buffers 28 which latter arepreloaded against the bearings 29 and 30, which bearings are thuspressed against collars31 and 32 of said bearings 22 in which shaft 20-is supported.

It will be seen that there is thus created a two-mass system comprisingthe large mass of the centrifuge housing 23, 24 which vibrates only inan axial direction, and the small working mass 1S, 19, 20 which rotatesand simultaneously oscillates in an axial direction, posed between thesaid two masses are operable means in the form of preloaded spring orbuffer arrangement 28, the bearings 29 and 3l) and the spring abutments33. In this manner the vibration-producing mechanism is left independentof any rotary motion, this being done by elastic means and in a mannertending to reduce the stresses imposed on the component parts of themachine. Vibrations may be excited in this oscillating system either bymeans of a single eccentric weight 34 or by'means of two such weightsarranged to act in opposition to one another, these weights beingmounted on the centrifuge housing 23, 24 by suitable brackets 35.

During operation of the embodiment of Figure 3 the shaft 20. rotates thedrum 18, this rotationproducing Ythe centrifugal acceleration necessaryfor a centrifuging 2action. At the same time the eccentric weights 34mounted on the elastically supported housing 23 are rotated in oppositedirections, causing vibrations in the longitudinal direction` of thecentrifuge, i. e. in the direction ofthe double-headed arrow X-X. Thislongitudinal -oscillation is set up because in any other position of theone another. The housing section 24 will oscillate axially Inter- 4togetherwiththe.housing 23, the partition` 27 and, the sets of springsor rubber buffers 28 serving to transmit the oscillations to the rotor.It is preferable that the masses in question and the spring constantsshould be selected in such a manner as to produce resonance.

For an advantageous operation of the arrangement just described it isessential that the sets of springs 28 are pressed against the collars 31and 32 of the shaft 20 or its bearing sleeves by way of the abutments33, and the bearings 29 and 30 which are preferably formed byanti-friction bearings. In this manner the anti-friction bearings remainunder preload and no chatter can develop. It will thus be seen that inthis case only the axial vibrations are superimposed to the rotation ofthc shaft 20.

In Figure 4, which illustrates a modied embodiment of the invention,those parts which correspond to similar parts in Figure 3 bear similarreference numbers. These two embodiments differ only in that differentarrangements are used in the vibration-producing mechanisms. Accordingto Figure 4 the housing 24 of the vibrationproducing means has nopartition, but the buffers are arranged so as to abut against the innerend walls of said housing, whereas on the inside, i. e. remote from saidend walls, said buiers abut against ring members 33 which in turn pressagainst the bearings 29 and 38 which again are held under preloadagainst a collar 36 of the drive shaft 20. Otherwise thisvibration-producing mechanism is identical with that described inconnection with Figure 3.

The embodiment illustrated in Figure 5 is characterized by the fact thatonly a small number of bearings are used. Moreover, in order to reducethe bulk of the machine, the eccentric weights 34, together with theirrespective brackets 35, are mounted on the housing section 24. Otherwisethe construction of this embodiment is identical with that of theembodiments of Figures 3 and 4.

As will be seen in Figure 5, the rubber buffers 28 or equivalent sets ofsprings are mounted between the end walls of the housing members 23 and24 on the one hand and the radial flanges 37 and 38 on the other, whichflanges are formed on members forming the bearing structure supportingthe shaft 20. The flange 37 lis integral with the bearing housing of theshaft 20, whereas the flange 38 is integral with a sleeve 39 which isslidably mounted and embraces the housing of bearing 49. The shaft 20 iscarried in the bearing housing in two tapered vroller bearings 40 whichserve to transmit to the shaft 20 the vibrations occurring in thedirection of the doubleheaded arrow X-X. The preload on the springelements 28 acts through the sleeve 39 to maintain the above mentionedparts in mutual contact.

Also the embodiment of Figure 5 gives a simple construction and ease ofassembly permits the tension of Ythe spring elements to be adjusted tosuit requirements of the practice, to eliminate rotation of the partshoused in the section 24 and also to reduce the number of bearingsrequired. It is, of course, necessary to provide a gap 41 between thebearing arrangement for the shaft and the housing 23 to thereby permitlongitudinal movement of the rotor assembly which tends to oscillate toa higher degree in the-presence of resonance.

The embodiments shown in Figures 3 to 5 may be modified in accordancewith Figure 6 by causing the two relatively. oscillating masses to bemoved by a spring drive mechanism comprising an eccentric shaft 42vsupported yby the housing 24', a push rod 43 and a drive spring d4.

The arrangements hereinbefore described may also be used to goodadvantage in machines of the vertical type as well as in machines havinga non-perforated centrifuging drum. Where it is possible, in view of themasses involved, to increase the amplitude of the oscillations, theeccentric weights used to produce the` Vibrations may be replaced withelectro-magnetic means or an elastically coupled crank. The features ofthe invention here disclosed may also be used in the appropriate senseto produce superimposed torsional vibrations.`

Various other changes and modications may be made without departing fromthe spirit and scope of the present invention and it is intended thatsuch obvious changes and modications be embraced by the annexed claims.

Having thus particularly described the invention, what is claimed as newand desired to be secured by Letters Patent is:

1. A centrifuge system having a screen drum body and a rotatable driveshaft to which said body is connected; housing means biased against asupport therefor and enclosing said drum and said shaft, eccentric meansrotatably supported by said housing means and constructed to pro duceoscillations of said housing means in substantially axial direction ofsaid drive shaft, journal means for said drive shaft to support thelatter during rotation thereof, and operable means supported in saidhousing means and positioned to extend along substantially the entireshaft and intermediate said journal means, said operable meanstransferring said oscillations of said housing means to said shaft,whereby the latter in addition to its rotationalmovement performs alsooscillations in axial direction thereof, resulting in an increasedoutput of said drum.

2. A system according to claim l, said operable means including centralabutment means, elastic buffer means arranged at either side of saidcentral abutment means, and outer abutment means for said buffer means,said buffer means being preloaded between both said abutment means.

3. A system according to claim 2, wherein said journals are operativelyconnected to said outer abutment means.

4. A system according to claim 2 including rubber buffers, said centralabutting means being mounted on said shaft and abutting said buffermeans which are arranged for position against the inner faces of saidouter yabutment means, thus producing Va non-harmonic springcharacteristic, and two thrust bearings, respectively engaged betweensaid outer abutting means and adjacent portions of said housing meanswhich carry said journal means and said shaft.

5. A system according to claim 2, in which said central abutment meansforms a circular partition connected With said housing means, saidpartition being provided with a central opening for the passage of saidshaft, said outer abutment means being mounted on said bearings, whichare supported against collars provided on said journal means for saidshaft.

6. A system according to claim 2, said housing means including inner endwalls forming said outer abutment means.

7. A system according to claim 2, said housing means mounted on saidbearing sleeve, and roller bearing means for said shaft seated in saidbearing sleeve.

8. A system according to claim 4, said operable means including adouble-acting spring arrangement connected to said drum and said shaftand constituting a relatively smaller vibration mass than the massformed by said enclosing means with said eccentric means, whereby said-oscillations in axial direction of said shaft caused by said eccentricmeans are of an amplitude inversely proportional to the weight of saidenclosing means.

9. A centrifuge system having a screen drum body and a rotatable driveshaft to one end of which said body is connected; means enclosing saiddrum and the major p0rtion of said shaft and yieldably supported on abase, ec-

centric means operable on said enclosing means and constructed so as toproduce during operation oscillations of said enclosing means onlyeffective axially of said drive shaft, bearing means supporting saiddrive shaft, and operable means supported Iby said enclosing means andoperatively connected to and extending between said bearing means tothereby transfer said oscillations produced by said eccentric means viasaid enclosing means to said shaft, whereby the latter in addition toits rotational movement performs also oscillations in axial directionthereof, resulting in improved efficiency of said drum.

10. A system according to claim 9, said eccentric means comprising twooppositely rotatable eccentric weights ea-ch connected to auniversal-joint shaft, and drive means rotating said universal-jointshafts in unison.

11. A centrifuge system having a screen drum body and a rotatable driveshaft connected adjacent one of its ends with said body; comprisingmeans yieldably supported on a base and enclosing said drum and at leasta part of said shaft, oscillation-producing means connected to saidenclosing means and constructed to produce oscillations of saidenclosing means effective axially of said drive shaft, bearing meanssupporting said drive shaft, and operable means carried by saidenclosing means and operatively connected to said bearing means andlocated to extend therebetween to thereby transfer said oscillations tosaid shaft, whereby the latter in addition to its rotational movementperforms also oscillations in axial direction thereof, to therebyenhance the efficiency of said drurn.

12. A system according to claim 1, in which said eccentric meanscomprise an eccentric shaft supported by said housing means, a push rod,and spring means between the push rod and said shaft and acting in axialdirection of said shaft.

References Cited in the le of this patent UNITED STATES PATENTS 456,968Seymour a Aug. 4, 1891 1,948,800 Revelart Feb. 27, 1934 2,254,455Sorenson Sept. 2, 1941 2,361,767 Hays Oct. 31, 1944 2,437,651 RasmussenMar. 9, 1948 2,494,584 Rouse Jan. 17, 1950

